1. Field of the Invention
The present invention relates to a speaker system for audio systems, televisions, or the like, and more particularly to a speaker system in which bass sounds discharged rearward to a speaker are amplified to improve bass quality.
2. Description of the Related Art
Generally, a speaker converts an electric signal into a sound wave signal and radiates the sound wave signal into free space. A cone speaker is the most frequently used conventional speaker. In a cone speaker, if a strong cylindrical magnetic field is created in a magnet which is located between a center pole and a yoke, as current is applied to a voice coil which is disposed in the magnetic field, force is induced to vibrate a conical vibrating board, made of paper for example, to thereby radiate sound waves.
Since the force is constant regardless of a frequency, it is possible to obtain flat frequency characteristics over a wide range of frequencies. The low frequency zone of the speaker system is restricted by a minimum resonance frequency that can be determined in a known manner by an equivalent mass including a radiation mass and a compliance due to edge, damper, etc. The high frequency zone is restricted by divided vibration due to a limit in the rigidity of a cone paper.
In divided vibration, since a small diameter of cone yields a higher frequency, speakers having the same structures and different cone diameters are used in combination to radiate sound waves having a wide range of frequencies.
In addition to the minimum resonance frequency, the low frequency zone radiation is influenced by the size of a cabinet containing the speaker. This is because when the cone is vibrated to radiate the sound waves, counter phases are generated in the forward and rearward directions of the cone and may interfere with each other, so that the sound waves are not properly radiated in the low frequency zone. Accordingly, in order to obtain sound waves of low frequency, the size of the cabinet must be somewhat large. This prevents an audio system, television, or the like, from being compact.
A speaker system for obtaining sound waves of low frequency without enlarging the size of a speaker cabinet is disclosed in the Korean patent publication No. 92-5066. FIG. 1 illustrates a cross-sectional view of the speaker system disclosed therein. The speaker system includes a speaker 2 which is disposed in a speaker housing 1 and has a diaphragm 2a for converting an electric signal into a sound wave signal; a sound wave collector 3 for collecting sound waves generated by the vibration of the diaphragm 2a; a wave guide 4 for transmitting the sound waves collected by the sound wave collector 3; and a horn 5 for radiating and amplifying the sound waves outputted from the wave guide 4. A tube 6 which is provided with an opening having the same diameter as the maximum diameter of the diaphragm 2a, is secured to a frame of the speaker 2 in one end thereof to integrate the sound wave collector 3 with the wave guide 4. The horn 5 is attached to the other end of the tube 6.
Referring now to FIG. 2 which illustrates a cross-sectional view of another conventional speaker system, a tube 6 which defines a wave guide 4 has a portion that runs parallel to a center axis of a moving coil to radiate sound waves and a portion that bends toward a horn 5 facing a forward space of a speaker system. Accordingly, the sound waves radiated toward a rear position of the housing 1 are amplified in the tube 6 while passing through a sound wave collector 3 and the wave guide 4, and thereafter are radiated through the horn 5 toward the front of the housing 1.
However, the conventional speaker systems constructed as mentioned above suffer from drawbacks in that although a portion of the bass sound waves radiated rearward of the speaker can be amplified to some extent, since the sound waves radiated rearward of the speaker are totally transmitted through the wave guide 4 and the horn 5, serious interference occurs between the sound waves radiated rearward of the speaker that have a frequency lower than a desired level. Particularly, bass of a very low level can not be properly amplified and clearness of the resulting sound is severely deteriorated due to compression of the sound waves. Also, because the wave guide 4 and the horn 5 must collect all the sound waves radiated rearward of the speaker, the sizes of the wave guide 4 and the horn 5 are large, which results in enlargement in the size of the speaker housing. Accordingly, it is difficult for the speaker system to be applied to audio systems, televisions, or the like, which are compact. Moreover, when molding a one-piece tube which has a geometric configuration, the size of a mold must be large, which in turn increases overall manufacturing costs.
Accordingly, the present invention has been made in an effort to solve the above problems occurring in the prior art, and an object of the present invention is to provide a speaker system which collects and amplifies only a portion of sound waves which are radiated rearward of a speaker to increase bass sound amplification efficiency and to ensure clearness of the resulting sound.
Another object of the present invention is to provide a speaker system which is small and light-weight.
Still another object of the present invention is to provide a speaker system in which a sound wave amplifying horn for amplifying sound waves is assembled from pieces in a detachable manner, to ease manufacturing operation and to reduce costs thereof.
According to one aspect of the present invention, there is provided a speaker system comprising: a speaker having a cone which converts an electric signal into a sound wave signal; a frame attached to a rear side of the speaker and having a plurality of sound wave radiating holes formed therein; and a sound wave amplifying horn for amplifying and radiating only a portion of sound waves which are radiated rearward of the frame.
According to another aspect of the present invention, the sound wave amplifying horn collects and amplifies sound waves radiated through at least one of the sound wave radiating holes.
According to another aspect of the present invention, the sound wave amplifying horn includes a plurality of sound collecting parts which collect sound waves radiated through the sound wave radiating holes, and an amplifying part which amplifies sound waves collected in the sound wave collecting parts.
According to another aspect of the present invention, a minimum diameter of the amplifying part is equal to the sum of diameters of the sound wave collecting parts.
According to another aspect of the present invention, an echo opening is formed in a housing for the speaker to discharge sound waves which are not collected in the sound wave amplifying horn.
According to another aspect of the present invention, the sound wave amplifying horn includes a first amplifying member which has a gradually increasing diameter, and a second amplifying member which is detachably assembled to the first amplifying member.
According to another aspect of the present invention, the sound wave amplifying horn includes a discharging horn formed in one end thereof to discharge amplified sound waves.
According to another aspect of the present invention, the first amplifying member includes a sound wave collecting part which collects only a portion of the sound waves radiated through the sound wave radiating holes.
According to another aspect of the present invention, the first amplifying member includes a plurality of engaging grooves formed on both sides thereof, and the second amplifying member includes a plurality of engaging protrusions fitted in the engaging grooves respectively.
According to another aspect of the present invention, the first amplifying member includes a plurality of guide holes formed on both sides thereof, and the second amplifying member includes a plurality of guide pins inserted into the guide holes.
According to still another aspect of the present invention, at least one of the first and second amplifying members has an elastic grip for holding electric wires.
The speaker systems according to the present invention provide advantages in that, since only a portion of sound waves which are radiated rearward of a speaker are collected and amplified, reflected waves or standing waves will not be generated in a sound wave amplifying horn. This increases amplification efficiency of bass sounds to improve clearness of sounds. Also, since design and manufacturing of the speaker can be performed easily and the size of the speaker can be reduced, the speaker can be applied to compact audio systems and televisions. Further, since the sound wave amplifying horn is detachably assembled, overall manufacturing costs can be reduced and the assembling operation can be carried out in a convenient manner.